In recent years, as picture quality and resolutions of screens improve, complexity of animations and images processed by a display card also increases. However, during processing of complex animations or images, a display card needs a relatively long time to perform computation, and when a computation time cannot match a refresh rate of a display, a phenomenon of discontinuous frames occurs. To resolve this problem, some display devices can dynamically adjust a refresh rate, so as to reduce the refresh rate when a display card performs complex computation, thereby maintaining smooth frame output.
However, under the limit of material characteristics, when a refresh rate is reduced, brightness of a screen is reduced accordingly, causing problems that frames of a display device have uneven brightness and flicker when the refresh rate changes. Therefore, how to maintain stable brightness of a screen during dynamic adjustment of a refresh rate is an research subject in the field.